1. Field
Example embodiments relate to a method of manufacturing a thin film transistor and a thin film transistor manufactured by the same. Other example embodiments relate to a method of manufacturing a thin film transistor, in which a semiconductor layer and a gate insulating film may be formed through ink jet printing using a single bank, thereby simplifying the manufacturing process and decreasing the manufacturing cost, and a thin film transistor manufactured by the same.
2. Description of the Related Art
A thin film transistor (TFT) is used as a switching element and/or a driving element for sensors, memory devices, optical devices and/or active matrix (AM) flat panel displays. The main field of application thereof is for AM flat panel displays, for example, AMLCD and/or AMOLED, the driving voltage of which is controlled by a TFT which is connected to each pixel region.
The structure of the TFT may be two different types, for example, a coplanar type, in which a source and a gate are placed in the same plane, and a staggered type, in which a source and a gate are not placed in the same plane. The staggered type TFT may be further subdivided into an inverted staggered type, in which a gate electrode may be placed under source/drain electrodes, and into a normal staggered type, in which a gate electrode may be placed above source/drain electrodes. The inverted staggered type may be also referred to as a bottom gate type, and the normal staggered type may also be referred to as a top gate type.
A bottom gate type TFT may be manufactured by sequentially forming a gate electrode, a gate insulating film, source/drain electrodes, and a semiconductor layer on a substrate, and a top gate type TFT may be manufactured by sequentially forming source/drain electrodes, a semiconductor layer, a gate insulating film, and a gate electrode on a substrate. For patterning in the above respective steps, deposition, photolithography, and etching may be repeatedly conducted, and a mask may be required in every step. However, deposition must be performed at relatively high temperatures ranging from about 300° C. to about 500° C., and photolithography may incur increased preparation expenses for a mask for patterning. Thus, the manufacturing cost may vary with the number of masks used in the manufacturing process. Also, there is a need for relatively expensive exposure equipment, leading to increased equipment expenses.
Various display devices may have increased display quality and the same flexibility as paper. In addition, process simplification and cost reduction may be important to the manufacturing process. Therefore, an organic thin film transistor (OTFT) may be expected to fulfill requirements for flexibility, process simplification, and cost reduction. However, conventional amorphous silicon TFTs and OTFTS may be disadvantageous because they are manufactured based on a conventional TFT process, and simplifying the process may be relatively difficult.